Plastic container with non-cylindrical body reinforced with peripheral grooves

ABSTRACT

The invention concerns improvements to containers, in particular plastic bottles, having a body ( 2 ) with a circular non-cylindrical wall, so as to reinforce them and prevent cross-section variation when they are subjected to compression forces. Part at least of the wall is provided with a substantially planar relief. The wall is reinforced with peripheral grooves ( 26, 27, 28, 29 30 ) oriented in planes substantially perpendicular to the longitudinal axis (X) of the container, and the part comprising a substantially planar relief is run through with several grooves. The invention is characterized in that the width of each of the grooves is such that it is less wide (L 2 ) where it emerges in said part of the wall than at the middle (L 1 ) of its crossing. The invention is particularly useful for reinforcing large capacity bottles.

[0001] A purpose of the invention is to improve containers made ofplastic material, the non-cylindrical body of which is reinforced byreinforcing means composed of peripheral grooves. It can be applied toany type of container the body of which has at least one wall part withan appreciably flat relief, which is the case with bottles. It alsoapplies, and quite particularly, to bottles the body of which has across section that is generally quadrilateral in shape, with roundedcorners, intended to contain so-called flat [liquids], i.e., with nointernal pressure.

[0002] Throughout the text of the present application, the termsrelating to a spatial position of a container or of various parts of acontainer relative to each other should be understood as being when thecontainer is standing, that is, oriented vertically along itslongitudinal axis, with the bottom down and the neck up. This is trueparticularly, but not exclusively, for the terms above, below, lower,upper, up, down, height, vertical, horizontal, etc.

[0003] It is known that containers made of plastic material are becominglighter and lighter, which creates problems in obtaining good mechanicalstrength both in the longitudinal as well as in the transversaldirection.

[0004] Consequently, when they are picked up, especially after beingopened, they have a tendency to crush, which could cause the contents tobe discharged, particularly when said contents are liquid.

[0005] When the containers are closed, compression forces occur whenthey are stacked on top of each other during storage or transport. Iftheir walls are not sufficiently rigid, the result is an increase in thecross section of the body of each of the containers supporting others.This is due to the fact that the pressure exerted above a containercauses its shoulders to sag, thus increasing the internal pressure ofthe container, which then affects the internal walls. If the containersare strapped to each other, the risk is then that, when the crosssection is increased, the stresses exerted between two adjacentcontainers become excessive, which can lead to mutual damage bycompression, for example.

[0006] These disadvantages are partially remedied by producingcontainers having a succession of reinforcing grooves at the peripheryof their body. However, although this solution has proven generallysatisfactory for containers having a body with cylindrical crosssection, both when they are handled after being opened as well as whenthey are stacked, this is not the case for containers having at leastone wall part with appreciably flat relief, such as containers having abody with cross section that is generally quadrilateral in shape, withrounded corners, particularly when they are stacked. This frequentlyresults in a significant increase in their cross section, by outwarddeformation of the parts of flat walls between two successive grooves.

[0007] These phenomena become more acute as the internal volume of thecontainers increases (more liters) and/or when the hydrostatic pressureexerted by their contents is large. Indeed, when forces due tohydrostatic or other pressure tending to increase the cross section ofthe walls of a container are present, they tend to be exerted more atthe center of the flat or appreciably flat areas than on their edges.This explains the outward deformations of the parts of walls between twosuccessive grooves that can be observed in these known containers.

[0008] A purpose of the invention is to remedy these disadvantages.

[0009] According to the invention, a container made of plastic material,having a body oriented along a longitudinal axis, with a non-cylindricalwall around this axis, the wall being reinforced by peripheral groovesoriented along planes that are appreciably perpendicular to saidlongitudinal axis, at least one part of said wall having an appreciablyflat relief and being traversed by several grooves, is characterized inthat the width of each groove traversing the part of wall having anappreciably flat relief is variable, the variation in width of each ofsaid grooves being such that it is less wide at its end in said wallpart than in the middle of its crossover.

[0010] It will be noted that this special structure makes it possible toavoid significant outward deformations of the wall parts that areappreciably flat, between two successive grooves.

[0011] According to another feature, a projection of the bottom of agroove, on its orientation plane that is appreciably perpendicular tosaid longitudinal axis, traversing a part of wall having an appreciablyflat relief, has, at least along the crossover, a curved profile with aconcavity turned toward the outside of the wall.

[0012] This particular shape gives greater rigidity to the bottoms ofthe grooves, which makes it possible to limit the deformations theyundergo during recovery from stresses.

[0013] According to another feature, the walls of the grooves have acurved profile.

[0014] In this way the creation is avoided of angular areas that couldbreak under the effect of stresses due to pressure, shock or otherphenomena.

[0015] Other characteristics and advantages of the invention will appearfrom the following description of the figures, which illustraterespectively:

[0016]FIG. 1, a view in elevation of one form of embodiment of a bottlewith quadrilateral cross section, comprising a type of container towhich the present invention is applicable;

[0017]FIG. 2, an angular view of the bottle of FIG. 1;

[0018]FIG. 3, a view in perspective, slightly tilted, of the bottlerepresented in FIGS. 1 and 2;

[0019]FIG. 4, a cross-sectional view along line AA of the bottlerepresented in FIG. 1;

[0020]FIG. 5, a cross-sectional view along line BB of the bottlerepresented in FIG. 2;

[0021]FIGS. 6 and 7, cross-sectional views along lines CC and DD,respectively, of the bottle represented in FIG. 1.

[0022] The bottle, with longitudinal axis X, represented in FIGS. 1 to5, has a neck 1, a body 2, a bottom 3, and an intermediate part calledshoulder 4, between the body and the neck.

[0023] In a known way, in the example illustrated, the neck ends in athreaded part 5, allowing a threaded cap to be screwed on.

[0024] In the illustrated example, the body 2 of the bottle has a crosssection that is generally quadrilateral in shape, square in thisexample, with rounded corners, so that the wall of the body is composedof parts in the form of appreciably flat panels, two of which 21, 22 arevisible in FIG. 3, connected to each other by parts of rounded corners,three of which 23, 24, 25 are visible in said FIG. 3.

[0025] As can be seen more particularly in FIGS. 1 to 3, the wall isreinforced by peripheral grooves 26, 27, 28, 29, 30, all of which areappreciably oriented along planes perpendicular to the longitudinalaxis. Each groove encircles the body by traversing the differentappreciably flat panels 21, 22 and rounded corner parts 23, 24, 25. Theresult is that the wall, in a vertical direction, is composed of analternation of sections 31, 32, 33, 34, 35, 36 of wall having theabove-mentioned cross section that is generally quadrilateral in shape,with rounded corners, and peripheral grooves.

[0026] According to the invention, the peripheral grooves have avariation in width at least where they cross a part of wall having anappreciably flat relief. In the case of the bottle illustrated in thefigures, it is therefore at least where they cross each of the panels21, 22 that the width varies, and the variation in width of each of thegrooves is such that it is less wide at its ends in a panel than at themiddle of its crossover.

[0027] Thus, with the bottle illustrated by FIGS. 1 to 7, which has fourflat panels, each groove has at least four variations in width.

[0028] Moreover, in referring to FIG. 1, which is a view in elevation ofthe bottle, it can be seen on an appreciably flat panel that, forexample, the groove 26 has a width L1 in the middle of where it crossesthe panel, which is greater than its width L2 at each of its ends insaid panel.

[0029] Each of the other grooves has the same characteristics, so thatthe flat portions of sections 31, 32, 33, 34, 35, 36 delimited by thegrooves have less width where the grooves have greater width, and viceversa.

[0030] In other words, two successive grooves across said part ofappreciably flat wall, a panel in the case of the bottle illustrated inthe figures, are separated by a section of panel the width of whichchanges in inverse proportion to that of the grooves, that is, thissection is less wide at its middle than at its sides, at the end of thegrooves. In other words, two adjacent grooves are closer to each otherat the middle of their crossover of a panel than at their end.

[0031] This particular structure makes it possible to preventsignificant outward deformations of appreciably flat wall parts betweentwo successive grooves, particularly in the following way:

[0032] because of the reduction in width of the flat areas in the middleof the crossover, here sections of panels 31, 32, 33, 34, 35, 36, theseflat areas offer a limited surface area to stresses, while the surfacearea offered by the bottom of the grooves 26, 27, 28, 29, 30 at thatplace is greater, so that the deformation forces are absorbed by thebottom of the grooves. This bottom can be deformed, but the deformationdoes not exceed the plane passing through the flat areas on either sideof the groove;

[0033] at the edges, and therefore at the ends of the grooves, where thesurface area offered by a portion of the flat area between twosuccessive grooves is greater, the absence of deformation is explainedin part, first because the stresses that exist at that location areless, and second by a scaffolding effect achieved by the edges of thegrooves on either side of said flat area portion.

[0034] In the example illustrated by the figures, the successive groovesall have the same variations in width, on the one hand, and similar oridentical dimensions on the other. However, it will be noted that thissimilarity is not necessary, the essential part being that in the middleof their crossover of a flat part, the width of each groove is greater,and the width of each flat portion of a section is smallest.

[0035] In the form of embodiment illustrated by the figures,particularly in reference to FIGS. 2 and 3, it will be noted that thewidth of the groove continues to decrease until it reaches a value of L3less than L2 in the middle of its crossover of the rounded corner 23.However, it will also be noted that this arrangement is not essential,and that the width of the groove could remain constant and preserve thevalue L2 where it crosses.

[0036] The profile of the walls of each groove is composed of analternation of curves or windings. This prevents the creation of sharpangles that are often areas where breaking begins.

[0037]FIG. 4, which is a cross-sectional view along AA of FIG. 1, showsthat the bottom of the grooves, in the middle of panels 21, 37, is farenough away from planes P1, P2—indicated by broken lines—of the panels,so that if the forces tend to push the bottom of the grooves outward,when they are absorbing the forces, it is quite unlikely that thedeformation would become such that the bottoms reach the limits of theplanes P1, P2.

[0038]FIG. 5, which is a cross-sectional view along BB of FIG. 2, showsthat to the right of the rounded corners, the width of the grooves isless. However, at this location the stresses are usually less than inthe middle, so that the risks of cross-section increase here are nearlynon-existent.

[0039]FIG. 6, which is a cross-sectional view along CC of FIG. 1, thatis, a central cross section of the bottom of a groove 29, illustratesone preferred form of embodiment of the profile of the bottom of thegrooves that makes it possible to give them greater rigidity and tolimit the deformations they undergo when absorbing forces. According tothis form of embodiment, the projection of the bottom of the grooves, ontheir plane of orientation appreciably perpendicular to the longitudinalaxis X, has, at least along the crossover of the parts in the form ofappreciably flat panels, a curved profile, with a concavity turnedtoward the outside of the wall.

[0040] Finally, FIG. 7 shows, in cross section DD of FIG. 1, a centercross section of a portion 33 of wall having the above-mentioned generalquadrilateral shape, with rounded corners and flat parts.

[0041] The bottle according to the invention can be obtained by themethods called injection blow molding, that is, methods in which aperform of plastic material, previously obtained by injection, istemperature conditioned, then blow-molded, or alternatively stretchedthen blow-molded, in a finish mold.

[0042] It can then be obtained by extrusion blow-molding of a tubularparison.

[0043] Obviously, the invention is not limited to the forms ofembodiment described and specifically claimed; it encompasses allequivalents available to a person skilled in the art.

1. Container, particularly a bottle, made of plastic material, having abody (2) oriented along a longitudinal axis (X), with a non-cylindricalwall around this axis, the wall being reinforced by peripheral grooves(26, 27, 28, 29, 30) oriented along planes that are appreciablyperpendicular to said longitudinal axis, at least one part (21, 22) ofsaid wall having an appreciably flat relief and being traversed byseveral grooves, is characterized in that the width of each groovetraversing the part of wall having an appreciably flat relief isvariable, the variation in width of each of said grooves being such thatit is less wide (L2) at its end in said wall part than in the middle(L1) of its crossover.
 2. Container according to claim 1, characterizedin that the bottom of a groove (29) traversing a part of wall having anappreciably flat relief (21, 22) has, at least along the crossover ofthat part, a curved profile with a concavity turned toward the outsideof the wall.
 3. Container according to either of claims 1 or 2,characterized in that the profile of the walls of each groove iscomposed of an alternation of curves or windings.
 4. Container accordingto any of claims 1 to 3, characterized in that the body (2) has a crosssection that is generally quadrilateral in shape, with rounded corners,so that the wall of the body is composed of parts in the form ofappreciably flat panels (21, 22), connected to each other by parts ofrounded corners (23, 24, 25), and the peripheral grooves (26, 27, 28,29, 30) have a variation in width in their crossover of a panel (21,22), and the variation in width of each of the grooves is such that itis less wide at its ends in a panel than at the middle of its crossover.5. Container according to claim 4, characterized in that the width (L3)of a groove in the middle of its crossover of a rounded corner part (23)is less than that (L2) at its ends in the panels.
 6. Container accordingto claim 4, characterized in that the width (L3) of a groove in themiddle of its crossover of a rounded corner part (23) is equal to that(L2) at its ends in the panels.